1. Technical Field
The present invention relates to a threaded core, an injection molded apparatus for molding a lens barrel with the threaded core and a method for making a lens barrel using the injection molded apparatus.
2. Description of Related Art
The ongoing development in microcircuitry and multimedia technology has made digital cameras popular and in widespread use. High-end portable electronic devices, such as mobile phones and personal digital assistants, have become multi-functional. Many portable electronic devices are now equipped with a camera module. The camera module generally includes an optical module which includes a lens barrel.
An injection molded apparatus may be used to make the lens barrel. The injection molded apparatus includes a threaded core for molding the screw thread on the lens barrel.
Generally, the lens barrel is mounted in a holder via screw threads. It is desirable to maintain a torque force between the lens barrel and the holder in an appropriate range. If the torque force is too high, the rotation between the lens barrel and the holder will become difficult. If the torque force is too low, the lens barrel may deviate from the holder and result in eccentricity between the lens barrel and the holder.
A typical method to solve the torque problem is to process the threaded core of the injection molded apparatus by electro discharge machining (EDM), and then applying mold to make the lens barrel. However, the torque force between the lens barrel and the holder may still be unpredictable if the EDM process produced an insufficient mold. In addition, it cannot be repaired and must be replaced, reducing efficiency and increasing cost.
Therefore, a threaded core and injection molded apparatus capable of adjusting the torque force between the lens barrel and the holder is desired to overcome the above-described deficiencies.